1. Field of the Invention
This invention relates to a method of and apparatus for severing a sheet and spacing pieces cut therefrom.
2. Discussion of the Technical Problems in the Present Technology
Glass sheets are severed or cut into pieces by scoring the sheets and thereafter opening the scores. When the severing step is practiced on a moving glass sheet, i.e. scores between the leading and trailing edges are opened the side edges of adjacent pieces are separated from one another to prevent edge damage from the edges contacting one another. One such spacing technique is taught in U.S. Pat. No. 3,491,634. In general, U.S. Pat. No. 3,491,634 teaches a conveyor having a plurality of driven cylindrical rolls for advancing a glass sheet through scoring and snapping stations to sever the sheet into glass pieces having their leading edges aligned with one another. Mounted at spaced locations on the conveyor are two driven bowed conveyor rolls. The first bowed roll separates adjacent pieces at the center line of the conveyor and the second bowed roll separates the outer sections from one another. The limitation with the technique taught in U.S. Pat. No. 3,491,634 is that the conveyor rolls and bowed rolls should be driven at the same peripheral speed. If the peripheral speeds are different from one another, the portion of the sheet on the bowed rolls and the portion of the sheet on the straight rolls are subjected to different peripheral speeds which may result in scuffing of the glass surface. Further, moving the sections over two spaced bowed rolls requires extra travel which may result in excess glass edge contact.
U.S. Pat. No. 3,838,803, in general, uses three wheels to apply bending moment forces about a score to sever edge portions from a glass sheet and air jets for moving the severed edge portions from the glass sheet. Although this technique is acceptable for disposing of nonusable glass edge portions, it is not economical to use air jets for precisely controlling side separation of glass pieces as they advance along a movement path. U.S. Pat. No. 3,910,042, in general, teaches the use of individually driven adjustable wheels for vectoring sheets. This technique requires a plurality of rolls each individually driven and is expensive to construct.
As can now be appreciated, it would be advantageous to provide a system for sideward separation of adjacent glass pieces to prevent their edges contacting one another that does not have the limitations of the present available techniques.